DE2926000B2 - Stabilized 1,1,1-trichloroethane - Google Patents

Description

Examples of component e) include: diethylamine, triethylamine, diisopropylamine, di-secondary-butylamine, Amylamines, hexylamines, pyridines, picolines, morpholines, N-alkylmorpholines with 1 to 3 Carbon atoms in the alkyl group, pyrrolidine and N-alkylpyrrolidine also with 1 to 3 carbon atoms in the alkyl group.

The amines which are particularly distributable according to the invention are N-methylmorpholine, diisopropylamine and pyrrolidine.

In the following text of the description, percent always mean% by weight, unless otherwise stated.

If the 1,1,1 -Trichloräthan as components a) and b) the mixture of terL-Butylaikohol and 2-Methyl-3-butyn-2-ol is added, this binary mixture consists of 1 to 99% tert-butyl alcohol, and 99 up to 1% 2-methyl-3-butyn-2-ol, preferably from 25 to 80% terL-butyl alcohol and 75 to 20% 2-methyl-3-butyn-2-ol.

According to an advantageous embodiment, the 1,1,1-trichloroethane is used as component b) trioxane in added in an amount of 0.5 to 3% without 2-methyl-3-butyn-2-ol

Preferred C3 to Ce epoxides (component c)) are Epichlorohydrin, 2,3-epoxypropanol-l and its methyl ether, Ethyl ether, propyl ether, isopropyl ether, butyl ether (primary, secondary or tertiary), 1,2-propylene oxide, Styrene oxide, cyclohexene oxide and preferably 1,2-butylene oxide. 1.2 to 3% epoxy is preferred used, based on 1,1,1-trichloroethane.

Examples of the nitroalkanes, of which at least one and preferably a mixture of at least two such compounds are added are nitromethane, nitroethane and the two isomers Nitropropanes. Their proportion is preferably 1 to 2%, based on 1,1,1-trichloroethane.

It has been found that the combination of the aforementioned compounds is particularly advantageous proves and at a comparable concentration has a significantly higher stabilizing effect than the Sum of the stabilizing effects of the individual components.

The combination of the aforementioned compounds a) to c) can be further enhanced by adding the Component f).

The phenols used are monophenols, such as phenol itself. Cresols, ethylphenols, butylphenols and in particular p-tert-butylphenol, thymol, naphthols, Methylnaphthols, eugenol, ethers from Ci- or C2-alcohols and monophenols such as anisole, guaiacol, 2-ethoxyphenol; Diphenols, such as resorcinol, catechol, Naphthoquinone and especially hydroquinone; Ethers from Ci or C2 alcohols and these diphenols, such as hydroquinone monomethyl ether; Triphenols such as pyrogallol, phloroglucinol, hydroxyhydroquinone and Trihydroxytoiuole.

Examples of heterocyclic compounds as component f) with a nitrogen atom are pyrrole, N-alkylpyrroles, the alkyl group of which has 1 to 4 carbon atoms contains, preferably N-methylpyrrole; Indole, 1-methylindole, 2-butylindole, 2-phenylindole, 2-toluylindole, 1-benzylindole and the isomers of these compounds; Oxazole and isoxazole are examples of heterocyclic compounds having one nitrogen atom and one Oxygen atom.

Examples of heterocyclic compounds with 2 nitrogen atoms are imidazole and pyrazole. Pyrazoline. Pyrazolidine, imidazoline, imidazolidine, piperazine and their N-alkyl derivatives, the alkyl group 1 to 4 Contains carbon atoms, pyrazine, pyrimidine and pyridazine.

The preferred agents according to the invention consist of 1,1,1-trichloroethane and contain as a stabilizer combination:

a) 1 to 3% tert-butyl alcohol,

b) 0.5 to 2.5% 2-methyl-3-butyn-2-ol and up to 2.5% Trioxane,

c) 0.2 to 3% 1,2-butylene oxide,

d) 0.5 to 1.5% nitromethane and / or nitroethane,

e) 0.005 to 0.1% N-methylmorpholine and / or diisopropylamine.

The following examples serve to explain the invention in more detail:

example 1

Ι, ί, Ι-Trichloroethane was made with the following compounds offset:

a) tert-butyl alcohol 2.0%

b) 2-methyl-3-butyn-2-ol 1.5%

c) 1,2-butylene oxide 0.45%

d) nitromethane 13%

e) N-methylmorpholine 0.008%

The stabilized mixture obtained was subjected to the multiple distillation test; thereby will distilled four times in succession and with each distillation only the first 90% by volume caught. With each of the four distillates, the scratch or scratch test was carried out in accordance with the ASTM standard D 29 43-71 T carried out.

This scratch test serves to prove in which

S5 way the stabilizer combination in 1,1,1-trichloroethane the degradation of this chlorinated hydrocarbon solvent in the presence of aluminum or Prevents aluminum alloys. According to the test, a cleaned and degreased piece of metal,

■ ίο Quality AA 1100 (ASTM standard, corresponding to aluminum A 45 according to AFNOR) immersed in 50 ml of stabilized 1,1,1-trichloroethane at room temperature and with scratched with a soft steel rod. After a sufficient period of time (1 hour) for any reaction to occur can take place, the presence or absence of bubbles, the discoloration of the solvent or the presence of dark resinous products is noted.

The agent passed the test without any trace of reaction being observed on the aluminum panels became.

A very rigorous long-term stabilization test was also carried out according to the Regulations of the Federal Institute for Materials Testing of the Federal Republic of Germany (BAM). In this test three experiments are carried out with a mixture of 100 ml of stabilized 1,1,1-trichloroethane and 100 ml of toluene carried out:

_W i Experiment 1:

Addition of 18 g of aluminum in lamellas and 0.7 g of aluminum chloride

Experiment 2:

Same as experiment 1 + 1 g of zinc stearate

Experiment 3:

As in experiment I + 10 ml oleic acid.

For each experiment, the above genes were

see 18 h at a bath temperature of 514 ° C Held at reflux.

Then, as in Example 1, stabilized 1,1,1-trichloroethane was added distilled in three equal fractions, according to the standard DIN 51 751. Then were with 100 ml of each of these fractions mixed with 100 ml of toluene, excluding the above BAM experiment 1 carried out

The solvent was considered to have stabilized satisfactorily, with no violent exotherm Reaction was observed in the course of the six separately evaluated experiments.

The above agent passed this test without any violent exothermic reaction being observed became.

example 2 1, Containing 1,1-trichloroethane: a) terL-butyl alcohol 2.0% b) 2-methyl-3-butyne-2-o) 1.85% c) 1,2-butylene oxide 0.45% d) Nitroethane 13% e) Pyrrolidine 0.01%

successfully passed the multiple distillation test with subsequent scratch test and the BAM test, as described in Example 1.

example 3 1.7% 1, , 1,1-trichloroethane was mixed with: 2.0% a) tert-butyl alcohol 0.45% b) 2-methyl-3-butyn-2-ol 0.6% c) 1,2-butylene oxide 0.5% d) Nitroethane 0.005% d) Nitromethane c) N-methyl-morpholine

This stabilized mixture passed the two tests described in Example 1 with success.

Example 4 1,1,1 -Trichloroethane was mixed with:

a) tert-butyl alcohol 2.0%

b) 2-methyl-3-butyn-2-ol 1.5%

c) 1,2-butylene oxide 0.45%

d) nitromethane 1.3%

Γ) N-methylpyrrole 0.008 ^r / o

e) N-methylmorpholine 0.01%

This stabilized mixture successfully passed the two tests described in Example 1.

B e i s ρ ι e I 5

This example explains the addition of an amine to be used according to the invention, combined with the other stabilizing components; the following experiment was carried out for this purpose:

in 98 ml of stabilized 1,1,1-trichloroethane mixed with 2 ml of a mixture of mineral spirits and water (90 vol .-% mineral spirits and 10 vol .-% water) was 72 h kept boiling under reflux. Before and after the test, the pH of the solvent was measured. Stabilized with 1,1,1-trichloroethane as in Example 4, but without N-methylmorpholine, the pH went from 6.7 before the experiment back to 4.5 after refluxing for 72 hours. It is known that the At this pH value, solvents are particularly corrosive in degreasing machines.

With the 1.lJ-Trichlorethylene stabilized according to Example 4 on the other hand, which contained 0.01% N-methylmorpholine, the pH remained at 8.3 after boiling for 72 hours under reflux. At this pH value there is practically no corrosion at all in the degreasing machines instead of.

Example 6
1,1,1-trichloroethane was mixed with:

a) tert-butyl alcohol

b) 2-methyl-3-butyn-2-ol
cj methyl glycidyl ether

d) nitromethane

e) diisopropylamine

and passed with success
tests described.

Example 7

The composition of the following formulation also met the requirements of the two described in Example 1 Testing:

2.4%
2.1%
0.5%
1.3%
0.005%

the two in example 1

a) 1,1,1-trichloroethane 94.995% b) tert-butyl alcohol 2.5% b) trioxane 1.4% c) 1,2-butylene oxide 0.4% d) nitromethane 0.7% e) N-methylmorpholine 0.005%

Claims (6)

Patent claims: 1. Stabilized 1,1,1-trichloroethane, containing a combination of: a) 0.1 to 5% by weight, preferably 0.5 to 3.5 % By weight terL-butyl alcohol, b) 0.1 to 5% by weight, preferably 0.3 to 3% by weight of 2-methyl-3-butyn-2-ol and / or trioxane, c) 0.1 to 5% by weight, preferably 0.2 to 3% by weight, of at least one epoxide, if appropriate chlorinated, which contains 3 to 8 carbon atoms in the molecule, d) 0.1 to 3% by weight of at least one nitroalkane with 1 to 3 carbon atoms in the molecule, e) 0.001 to 1% by weight, preferably 0.005 to 0.1% by weight, at least ei) an aliphatic, secondary or tertiary, straight-chain or branched-chain Amine with 4 to 10 carbon atoms and basic character, e2) an aromatic amine derived from Benzene, substituted with halogen atoms or Cr to C3-alkyl groups and basic, _ Character or e3) a heterocyclic amine with 1 or 2 Nitrogen atoms in the molecule and basic character, as well f) 0 to 1 _{% by weight, preferably 0.001 to 0.1 J ()} % by weight, of at least one antioxidant from the following groups: fi) phenol group, namely phenol, cresols, ethylphenols, butylphenols, thymol, naphthols, methylnaphthols, eugenol, ethers from ₃ -Cr or C2-alcohols and monophenols, diphenols, ethers from Cr or Cj-alcohols and the aforementioned diphenols, triphenols or f2) the group of nitrogen-containing hetero _4U cyclen having 3 to 5 carbon atoms ,! or 2 nitrogen atoms and optionally one oxygen atom in the ring. 2. Stabilized 1,1,1-trichloroethane according to claim!, Characterized in that it is a mixture of 25 to 80 wt .-% tert-butyl alcohol and 75 to 20 wt .-% ^{as components 4 a) and b)} % Contains 2-methyl-3-butyn-2-ol. 3. Stabilized 1,1,1-trichloroethane according to one of claims 1 or 2, characterized in that it ^r '° as component c) epichlorohydrin, 2,3-epoxypropanol-1 or its methyl ether, ethyl ether, propyl ether, isopropyl ether, butyl ether Contains (primary, secondary or tertiary), 1,2-propylene oxide, styrene oxide, cyclohexene oxide or preferably 1,2-butylene oxide. ^{Γ) |} > 4. Stabilized 1,1,1-trichloroethane according to any one of claims 1 to 3, characterized in that it contains only 0.5 to 3% by weight of trioxane as component b). 5. Stabilized 1,1,1-trichloroethane according to one of ^W) claims 1 to 4, characterized in that it contains diisopropylamine, N-methylmorpholine and / or pyrrolidine as component e). 6. Stabilized 1,1,1-trichloroethane according to one of the Claims I to 5, characterized in that it '' "> contains as component f) N-methylpyrrole. It is known that 1,1,1-trichlorathane is unstable when it with metals such as aluminum or aluminum alloys and magnesium or magnesium alloys in Is brought into contact. This instability manifests itself in a decomposition with the simultaneous formation of Hydrogen chloride and other decomposition products as well as discoloration of 1,1,1-trichloroethane. This inconsistency is a significant disadvantage in the use of this chlorinated hydrocarbon as a solvent for degreasing and / or cleaning Workpieces or components made of metal. Numerous compounds have already been mentioned as agents for preventing decomposition or rls Stabilizers for 1,1,1-trichloroethane. In US-PS 23 71 644 monohydric aliphatic alcohols are described for this purpose, namely primary, secondary or tertiary alcohols. The tertiary alcohols, such as tertiary amyl alcohol, are stated to be less effective than the primary and secondary alcohols. The US-PS 30 00 978, however, can be seen that the tert-butyl alcohol should have a higher effectiveness than tert-amyl alcohol and also as sec-butyl alcohol, isopropanol, n-propanol or ethanol. In US-PS 23 71 645 cyclic ethers such as propylene oxide and isobutylene oxide are also described and according to CA-PS 6 27 411 1,1,1-trichloroethane is mixed with nitromethane. Taken individually, however, these components only cause inadequate resistance, above all if 1,1,1-trichloroethane for a long time when degreasing and / or cleaning metallic or other Workpieces or products is used. To improve the resistance of this chlorinated hydrocarbon solvent is according to GB-PS 9 12 118 at the same time a nitroalkane and an epoxy added or a nitroalkane and a monohydric aliphatic alcohol with up to 5 carbon atoms in the Molecule. But since 1,1,1-trichloroethane itself is particularly sensitive to decomposition in the Temperatures at which it is used as a degreasing agent and / or cleaning agent because of the presence of fats, metallic surfaces and metallic suspended in the cleaning bath Accompanying substances, these stabilizer combinations are not able to make 1,1,1-trichloroethane effective stabilize. Also the ternary combination of nitromethane, tert-butyl alcohol and 1,2-butylene oxide according to the US-PS 32 81 480, an amber-colored precipitate may appear in the solvent after 24 hours Do not prevent contact with aluminum. The same applies to aliphatic acetylenic alcohols with an OH group and fewer than 8 carbon atoms in the molecule, especially for 2-methyl-3-butyn-2-ol, the according to US-PS 28 38 458 .nit 1,4-dioxane are combined. The invention is based on the object of eliminating the known disadvantages and providing an effective and to enable long-term stabilization of 1,1,1-trichloroethane under strict conditions of use, for example the degreasing and / or cleaning of metallic workpieces, plastics, textiles or other materials without degradation or adverse change in the solvent or the Products that are being treated is observed. The subject matter of the invention is thus the stabilized one indicated in the preceding claims l.l.l-trichloroethane.